Internal power grids of wind power plants connect individual wind turbine generators of a wind power plant to a point of common coupling—the latter being the point where power is fed onto a power supply grid from the wind power plant.
In order to do this correctly the impedance of the internal power grid between each of the wind turbines of the plant and the point of common coupling has to be taken into consideration. Especially as the point of common coupling often is where the wind power plant has to fulfill the requirement in the grid code, i.e. grid connection specification.
The wind turbine generators experience impedance to the point of common coupling and thus needs to generate higher wind turbine generator voltage level in order to compensate for voltage drops in the internal power grid. The same applies for reactive power, as reactive power is absorbed in the internal cables.
Wind power plants are often controlled by a power plant controller. The power plant controller controls and communicates with the wind turbine generators and other components in the wind power plant. In order to control the wind turbine generators some measured electrical parameters are needed. The power plant controller and the measurement sensors may be located remotely from the point of common coupling, so due to the impedance in the grid the controlled parameters are not the same at the point of measurement and the point of common coupling.
It may be seen as an object of the embodiments of the present invention to provide a power plant controller that ensures proper values of electrical parameters in a point different from the point of measurement.